Enhanced supercharging system and an internal combustion engine having such a system

ABSTRACT

The invention refers to a supercharging system ( 6 ) for an internal combustion engine ( 1 ) incorporating in combination, a turbine ( 7 ), a compressor ( 8 ) and an electrical driven system ( 20 ) that is connected by any power transmission system ( 16, 19 ) to the crankshaft ( 4 ) or any other vehicle drive shaft of an internal combustion engine, where the turbine inlet is subjected to exhaust gases, causing the turbine wheel to rotate and thereby via the drive shaft causing mechanical rotating power.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuing application of co-pending applicationSer. No, 12/670,226 filed on Jan. 22, 2010, which is the 35 U.S.C. §371national stage of International PCT/SE 2008/050883 filed on Jul. 22,2008 , which claims priority to U.S. application Ser. No. 11/781,992filed on Jul. 24, 2007. The entire contents of each of theabove-identified applications are hereby incorporated by reference.

FIELD OF INVENTION

The present invention refers to a new, enhanced supercharging system foran internal combustion engine, and also to an internal combustion enginehaving such a system.

BACKGROUND OF THE INVENTION

Today there is a strong development going on in automotive industry inorder to find systems for decreasing over all fuel consumption. Thereare many technical areas, which together make up for a good result.

One good way of improving internal combustion engine efficiency is touse some kind of supercharging device to increase intake manifoldpressure in order to decrease the internal pumping losses. This in turnleads to decreased fuel consumption. R also makes it possible todownsize the engine without interfering with vehicle performancerequirements.

There are several different supercharging devices available but they canall be sorted to one of the following types:

-   From a vehicle drive shaft, such as for instance a crankshaft,    mechanical driven superchargers-   Exhaust driven turbo superchargers-   Electrical motor driven superchargers

In some applications more than one supercharging device may be used atthe same engine.

JP published patent application No 2000-230427 refers to an internalcombustion engine with a supercharger, which via a clutch adapted toconnect and disconnect the engine and the supercharger.

WO 2004/025097 A 1 discloses a method for operating an internalcombustion engine having a turbocharger with a separate compressordriven via a belt-drive from the engine crankshaft, said compressorbeing connected to the net of the turbocharger for increasing thepressure of the intake aft delivered to the turbocharger This means thatthe losses increase due to additional pressurized conduits between theseparate compressor and the turbocharger, and also increased mechanicalcompressor losses at high motor speeds.

PURPOSE OF THE INVENTION

The purpose of the present invention is to combine all these differentpropulsion modes into one supercharging device in order to make benefitof the different properties associated with the different propulsionmodes The purpose is also to provide a possibility of convertingoverflow energy from the exhaust gases to electric energy, that can beused to recharge the battery if required The supercharging deviceaccording to the invention shall be practically applicable on existinginternal combustion engines and it shall be possible to propel the netsupercharging device with all defined types of propulsion modes.

BRIEF DESCRIPTION OF THE DRAWINGS

Hereinafter the invention will be further described with reference toschematically shown embodiments.

FIG. 1 is a schematical side view of an internal combustion engineequipped with a supercharging system according to the invention,

FIG. 2 illustrates schematically in block form a principal lay out forthe supercharging system according to the present invention,

FIG. 3 shows schematically in a side view an embodiment of thesupercharging system according to the invention, and

FIG. 4 is a further schematically shown embodiment of the superchargingsystem, according to the invention,

FIG. 5 shows in a view resembling to FIG. 1 a modified embodiment of aninternal combustion engine equipped with a supercharging systemaccording to the invention,

FIGS. 6-16 illustrate schematically further alternative embodiments ofthe supercharging system according to the invention.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT

The proposed solution described in the drawing figures combines amechanical supercharging system, an electricalsupercharging/regenerating system and an exhaust gas propelled turbosupercharging system, which are arranged on a common shaft. This shaftin turn is connected by means of a one way clutch unit to themechanically propelled shaft, coupled to any engine drive shaft.

FIG. 1 shows schematically an internal combustion engine 1 having an aftintake manifold 2, and an exhaust gas manifold 3. In the embodimentschematically illustrated there are four aft intake pipes intimatingthat the engine has four cylinders, although the number of cylinders canbe higher as well as lower. The engine 1 has a crankshaft 4, which isequipped with a pulley 5.

A supercharging device 6 is attached directly to the engine block in asimilar way that turbocharging systems are attached today. Thisturbocharging device 6 incorporates a turbine 7 and a compressor 8arranged on a common shaft 9, where the turbine is driven by the exhaustgases from the exhaust gas manifold 3, and the co-rotating compressorimpeller 8 is compressing ambient aft which is sucked in via an aftfilter 10. The compressed air is in a duct 11 via an intercooler 12 anda throttle 13 introduced in the air intake manifold 2, whereas theexhaust gases after having passed the turbine are evacuated via, anexhaust gas conduit 14 with a catalyzer 15.

The pulley 5 rotating with the crankshaft 4 of the engine, transfers viaa belt drive 16 rotation to a shaft 17, which via a one way clutch 18,can be coupled to the shaft 9, on which the turbine 7 and the compressor8 are arranged, thus that the rotation of the crankshaft 4 can betransferred to the shaft 9 common for the compressor and turbine, insituations where the turbine has not reached its working area.

For regeneration of rotary power to electric, power, the common shaft 9is connected via a belt drive 19 to an electric machine 20, a battery orthe like. The engine also incorporates an engine brake valve 21 and awastegate 22.

For fitting a supercharging device as described to existing internalcombustion engines it is of course necessary to design this device insuch a way that it compiles with existing power conversion nodes, i.e.the exhaust gas intake has to be situated for corresponding to theexhaust manifold outlet and the mechanically driven power conversionnode has to be located in line with existing outputs for auxiliary loadsfrom the internal combustion engine.

The following technical advantages of the supercharging device asdescribed can be identified, and which mostly arise from the possibilityto use each separate sub-system in this concept at its best efficiencyinterval:

-   No, or very low mechanical compressor losses at high engine speeds.-   Regeneration of energy, to electric power, from the supercharging    device, when it has its best efficiency.-   The compressor shaft may help the turbine to reach its working area    quicker.-   One supercharging device, one axis, three different driving modes.-   No losses due to additional pressurized pipes between compressor and    turbine.-   No turbo-lag,-   Easy to implement on almost any of today's existing combustion    engines.-   Possibility to regenerate overflow power from the exhaust gases to    electrical power via the electric motor/generator.-   Possible to momentary assist the mechanical supercharging system by    electrical drive if needed, Le. during very low engine speeds or to    maintain boost pressure during fast speed transients.-   Gains in terms of engine room space.

FIG. 2 illustrates schematically in block form a principal lay out forthe supercharging system according to the present invention, in which isshown a turbine 7 and a compressor 8 arranged on a compressor shaft 8 a. Via a clutch 123, which for instance can be a one way clutch, thiscompressor shaft 8 a can be connected to and disconnected from a ring 24forming part of a planetary gear 25, having planet wheels 26 connectedto a planet wheel carrier and cooperating with a sun wheel 27, which isfitted to a shaft 28 rotatably supported and provided with a pulley 29,which via a transmission, such as a belt drive 16, is connected to apulley 5 arranged on a drive shaft of the engine, such as the crankshaft4 thereof, or the like. The planet wheel carrier in turn is via atransmission 130, such as a belt drive, connected to an shaft 131 of anelectric motor 132, which is controlled by means of a controlelectronics device 133.

FIG. 3 and FIG. 4 illustrate schematically two slightly differingembodiments of the supercharging device according to the presentinvention.

Thus, FIG. 3 illustrates a turbine 7 connected via a shaft 9 to acompressor wheel 8. The shaft 9 is supported in bearings 34, 34 a , andcarries at its end, remote from the turbine 7 a pulley 31 a , which viaa not shown transmission, such as for instance a belt drive is coupledto a not shown generator in order to recover excessive energy from theturbine. In this embodiment of the supercharging device, the shaft 9 canvia a clutch 18, 230 be connected to and disconnected from a furthershaft 28, whereby the shafts 9, 28 when the clutch is in engagedposition interconnects the two shafts as a common axis. This secondshaft 28, which is supported in a bearing 34 and is equipped with aplanetary gear 25 for changing up the speed. At its opposite side thisfurther shaft 28 carries a further pulley 29, which via a (not shown)transmission, such as a belt drive, is connected to the crankshaft orany other driving shaft of the combustion engine for driving thecompressor 8 before the turbine has reached its working speed.

In FIG. 4 is shown another embodiment of a supercharging device which isslightly different from that as shown in FIG. 3.

In this embodiment of a supercharging device according to the inventionthere is like in FIG. 3 provided a shaft 9 carrying a turbine 7 and acompressor 8, and which shaft is journalled in rolling bearings 34, andplain bearing 34 a . The shaft 9 is connected to the ring 24 of aplanetary gear 25 which has an opposite shaft 28 coupled to the planetwheels of the planetary gear 25. At a short distance from the planetarygear the shaft 28, which forms a continuous axis with the shaft 9, isequipped with a pulley 31 a , which via a not shown transmission, suchas for instance a belt drive is coupled to a not shown generator. Afterthat pulley 31 a there is provided a further shaft which via a clutch 18can be connected to and disconnected from the shaft 28, and this furthershaft carries a further pulley 29, which via a (not shown) transmission,such as a belt drive, is connected to the crankshaft or any otherdriving shaft of the combustion engine.

FIG. 5 shows schematically an embodiment of an internal combustionengine 1 having an air intake manifold 2 with four air intake pipes, andan exhaust gas manifold 3, having four exhaust gas pipes for the fourcylinders of the engine. The engine 1 has a crankshaft 4, which isequipped with a pulley 5.

Attached to the engine block is a supercharging device 6, incorporatinga turbine 7 and a compressor 8 arranged on a common shaft 9. Thecompressor 8 has a compressor shaft 8 a projecting in the oppositedirection to the common turbine/compressor shaft 9. The turbine isdriven by exhaust gases from the exhaust gas manifold 3, and theimpeller of the co-rotating compressor 8 is compressing ambient airwhich is sucked in via an air filter 10. The compressed air is in a duct11 via an intercooler 12 and a throttle 13 introduced in the air intakemanifold 2, whereas the exhaust gases after having passed the turbineare evacuated via an exhaust gas conduit 14 with a catalyzer 15.

The pulley 5 rotating with the crankshaft 4 of the engine, transfers viaa belt drive 16 rotation to a shaft 17, which via a clutch unit 18, canbe coupled to an electric machine 20, which in turn is coupled to a ringgear wheel 24 of a planetary gear 25 with planet gear wheels 26 and asun gear wheel 27 connected to the compressor shaft 8 a . In this mannerthe shaft 9, on which the turbine 7 and the compressor 8 are arranged,thus can transfer the rotation of the crankshaft 4 to the shaft 9, insituations where the turbine has not reached its working area.

The engine also incorporates an engine brake valve 21 and a wastegate22. The brake valve 21 is controlled by way of a control box 23, whichbased on different engine behaviour parameters, will operate formaintaining the rotational speed of the turbine so high as possible inorder to avoid dangerous pressure increase at the exhaust side.

FIGS. 6 to 16 represent alternative versions of the layout of thesupercharging device according to the invention shown in schematic form,whereby the schematic representation according to FIG. 6 illustrates themain components of the embodiment according to FIG. 5, i.e. the turbine7 is driven by the exhaust gases from the engine 1.

The compressor 8 is arranged on the same shaft as the turbine 7, and theengine crank shaft 4 drives via a transmission 16 a pulley which via afreewheel/clutch 18 is connected to a shaft of an electric machine 20having a working speed of about 20000 rpm or more. Between the electricmachine 20 and the compressor shaft 8 is provided a planetary gear 25.

The embodiment illustrated in FIG. 7 differs to that according to FIG. 6in that the planetary gear 25 is positioned nearest to the clutch 18 andthe electric machine 20 is positioned outside the clutch 18.

In FIG. 8 is shown an embodiment wherein the clutch 18 is positionedbetween the crank shaft 4 and the transmission 16, whereas the electricmachine 20 is connected to the ring gear wheel of the planetary gear 25.

The embodiment shown in FIG. 9 corresponds to the embodiment accordingto FIG. 7, with the exception that the electric machine is connected tothe crank shaft 4, via the clutch 18 and an additional transmission 16a.

FIG. 10 shows an embodiment where the electric machine 20 is positionedbetween the turbine 7 and the clutch 18, whereas the planetary gear 25is positioned between the clutch 18 and the compressor.

FIG. 11 shows a further alternative embodiment where the turbine 7 andthe compressor are interconnected via a planetary gear 25, whereas theclutch 18 is connected between the crank shaft 4 and a transmission 16driving the electric machine, In this embodiment the planetary gear thusis integral with the turbo chamber housing.

In FIG. 12 is illustrated a mechanical embodiment where a firstplanetary gear 25 is positioned between the turbine 7 and the compressor8, whereas a second planetary gear 25 a and a clutch 18 are positionedbetween the engine crank shaft and the electric machine 20.

FIG. 13 illustrates an electromechanic solution, where the turbine 7drives a generator 28, which via a high-voltage connection feeds anelectric machine 20. A clutch 18 is provided between the electricmachine 20 and a pulley for the transmission 16, and between the pulleyand a compressor 8 is provided a planetary gear 25 The rotary speed ofthe generator 28 is preferably about 100,000 rpm, whereas the electricmachine has preferably a rotational speed of about 20,000 rpm.

In FIG. 14 is illustrated how the turbo shaft 9 interconnecting theturbine 7 and the compressor 8 is positioned in a dosed housing with theturbo shaft floating in a magnetic field. The solution is equipped withmagnetic clutches 30 and gas seals 31. A gear 32 is provided fortransferring power from a first planetary gear 25 to a second planetarygear 25 a.

FIG. 15 illustrates a hybrid transmission for high-voltage with a commonshaft 9, and a high-speed electric motor connected directly to theturbine shaft and with a high-voltage battery package 33 and ahigh-speed, high-voltage electric machine 20 b.

FIG. 16 finally illustrates an embodiment rather like the one accordingto FIG. 15, but where the electric motor surrounding the turbine shaftis connected to any part of the planetary gear and with a voltage of thebattery pack 33 of 600V, and the electric machine 20, 20 c has a voltageof 600V.

For easier description of the combined operation of this device thefollowing sub systems are defined.

Turbo Charged System

Turbo charging means good efficiency when activated, but is dependent onhigh rotational speed for the exhaust gases to have enough power topropel the turbine fast enough to build up substantial intake manifoldpressure.

Turbo charging has one major advantage in comparison to all other supercharging systems, as it uses overflow energy in the exhaust gases tocharge the intake manifold air.

By doing so no extra fuel is consumed in order to build up a good intakemanifold pressure. The principle intake manifold pressure as a functionof rotational speed has the following appearance:

Super charging means increased intake manifold pressure from lowrotational speeds and a proportional increase of intake manifoldpressure coupled to the rotational speed. Thus at higher rotationalspeed the efficiency of the supercharger becomes very poor due to highinternal friction and heat losses. The principle intake manifoldpressure as a function of rotational speed has the following appearance:

Electrical Super Charged System

Electrical super charged systems work in the same way as mechanicallyones but with the advantage that they provide the possibility to controlthe intake manifold pressure to a given level by providing power whenits needed but also to regenerate power from the exhaust gases whenpossible.

Existing Power Electronics Monitoring Systems

Algorithms for energy management are necessary to be able to regeneratepower into the electric system of the vehicle, Systems for this arealready developed in many vehicles of today. These systems are designedto keep track on the present auxiliary loads as well as monitoring thebattery status. If there is a need for the battery to be recharged andpower is available due to the fact that not all auxiliary systems areused, the system may raise the generator load voltage to startrecharging the system.

The algorithms can be reconfigured so that it in addition to therepresent application also regenerates the power provided from thissupercharging device into electric power when the battery is not fullycharged. By doing so for example during high-way driving the electricsystem would be better prepared for start-stop applications where afully charged battery is essential for a good start-stop operation.

In order to decide how and when the electric machine should act newalgorithms are needed to support the regenerating mode. By usingexisting hardware already in production, such as rpm-sensors, pressureand flow sensors together with modifications of existing electricmonitoring systems, this could be done.

Power Split and Defined Propulsion Modes

In order to clarify the different propulsion modes of this new inventionthe following power conversion nodes have been defined:

-   A: Chemical power (flow, pressure)=>Mechanical power (rotational    speed, Torque)-   B: Mechanical power (rotational speed, Torque)=>Chemical power    (flow, pressure)-   C: Generative: Electrical power (I₁ U)=>Mechanical power (rotational    speed, Torque)-   Regenerative: Mechanical power (rotational speed,    Torque)=>Electrical power (I₁ U).

SUMMARY

This invention provides a relatively easy way of reducing over all fuelconsumption by combining already existing systems in a new way. If thisinvention could be combined on an engine equipped with a start-stopsystem this would further “boost” this system as well by increasing theamount of times one can start the engine before the electronicmonitoring system (CEM) has to step in and shut down the start-stopapplication to avoid battery depletion.

The invention is not limited to the embodiments schematicallyillustrated in the drawings and described with reference thereto, butvariants and modifications are possible within the scope of the appendedclaims.

The transmissions described have been illustrated as belt drives, butany type of appropriate transmission units can be used. The clutch unitsmentioned can be mechanical one way clutches of any appropriate type,although electric clutches, viscous couplings and the like are alsopossible.

The invention claimed is:
 1. A supercharging system for an internalcombustion engine, comprising: a turbocharging device comprised of aturbine and a compressor; said compressor and said turbine arranged on acompressor shaft; a first planetary gear carried on said compressorshaft, said first planetary gear comprised of a first sun gear carriedby said compressor shaft and a first ring gear; a clutch unit; a powertransmission for connecting a crankshaft of the combustion engine tosaid first ring gear via the clutch unit, said power transmissioncomprised of a second planetary gear; said second planetary gearcomprised of a second sun gear and a second ring gear; and an electricmotor/generator connected to said power transmission and said secondplanetary gear, wherein the supercharging system delivers compressed airto the internal combustion engine during engine operation, and whereinsaid second planetary gear, comprised of said second sun gear and saidsecond ring gear, is aligned with said crankshaft.
 2. The superchargingsystem of claim 1, wherein said second planetary gear is configured toprovide a power split between said compressor shaft, said electricmotor/generator, and said crankshaft.
 3. A supercharging system for aninternal combustion engine, comprising: a turbocharging device comprisedof a turbine and a compressor; a first planetary gear a clutch unit; apower transmission for connecting a crankshaft of the combustion engineto power said compressor via the clutch unit; and an electricmotor/generator, wherein the supercharging system delivers compressedair to the internal combustion engine during engine operation, wherein,said compressor and said turbine are arranged on a compressor shaft,said first planetary gear is carried on said compressor shaft, saidfirst planetary gear comprised of a first sun gear carried by saidcompressor shaft and a first ring gear, said power transmissionconnecting the crankshaft of the combustion engine to said first ringgear via the clutch unit, said power transmission comprising a secondplanetary gear, said second planetary gear comprised of a second sungear and a second ring gear, said electric motor/generator connected tosaid power transmission and said second planetary gear, and said secondplanetary gear, comprised of said second sun gear and said second ringgear, is aligned with said crankshaft.
 4. A supercharging system for aninternal combustion engine, comprising: a turbocharging device comprisedof a turbine and a compressor; a first planetary gear; a clutch unit; apower transmission for connecting a crankshaft of the combustion engineto power said compressor via the clutch unit; and an electricmotor/generator, wherein, the supercharging system delivers compressedair to the internal combustion engine during engine operation, saidcompressor and said turbine are arranged on a compressor shaft, saidfirst planetary gear is carried on said compressor shaft, said firstplanetary gear comprised of a first sun gear carried by said compressorshaft and a first ring gear, said power transmission connecting thecrankshaft of the combustion engine to said first ring gear via theclutch unit, said power transmission comprising a second planetary gear,said second planetary gear comprised of a second sun gear and a secondring gear; and said electric motor/generator connected to said powertransmission and said second planetary gear, and wherein said secondplanetary gear is configured to provide a power split between saidcompressor shaft, said electric motor/generator, and said crankshaft. 5.The supercharging system of claim 4, wherein said second planetary gear,comprised of said second sun gear and said second ring gear, is alignedwith said crankshaft.